System and method to support data applications in a multi-homing, multi-mode communication device

ABSTRACT

A method of transmitting and receiving data from a multi-homing network device to a data network is disclosed and includes defining a network policy and transmitting the network policy to a routing module. Further, the method includes receiving a route scope from the routing module. The route scope identifies a subset of data interfaces to the data network that satisfy the network policy wherein the subset of data interfaces are selected from a set of available data interfaces and wherein the subset of data interfaces includes at least one data interface.

REFERENCE TO RELATED APPLICATIONS

The present application claims priority from U.S. Provisional PatentApplication No. 60/686,844 filed on Jun. 1, 2005.

BACKGROUND

I. Field

The present disclosure generally relates to network devices. Moreparticularly, the disclosure relates to multi-homing network devices.

II. Description of Related Art

In recent years, the number of wireless handsets in operation hasincreased dramatically. With the increase in demand for these mobiledevices, the manufacturers are building these devices to includenumerous data services. This convergence of data services can makewireless devices powerful resources for data networking. However, due tothe increase in data services provided by wireless devices, the numberof nefarious attacks on wireless devices has also increased. Hence,there is an increasing concern to protect these devices from maliciousattacks.

Wireless telephones have become multi-homing devices that include manydata interfaces through which the wireless telephones can accept andsend data. At any time, within a particular wireless telephone, morethan one of these data interfaces can be open for direct data transferwith the Internet, or another data network. The data protocol stack inthe mobile device is mostly transparent to the multiple data interfacesof the device. Further, the data protocol stack can accept data from anyof the data interfaces as long as the protocol address of the incomingdata matches the protocol address of the phone. As such, the wirelesstelephone is open and vulnerable to many attacks from the Internet andother data networks.

For example, when a packet is received on a data interface at amulti-homing device, the packet can be routed to an appropriate socket,or application. In general, for a socket that is connected usingtransmission control protocol (TCP), a packet is routed to the socketbased on four (4) tuples, e.g., source address (src_addr), source port(src_port), destination address (dst_addr), and destination port(dst_port). For a socket that is connected using user datagram protocol(UDP), a packet is routed to the socket based on two tuples, e.g.,destination address (dst_addr) and destination port (dst_port). Forother protocols, such as Internet control message protocol (ICMP) ornon-Internet protocol (IP) based protocols, other fields in the networkand transport layer headers can be used.

Unfortunately, in a multi-homing device the parameters described abovemay not be able to uniquely identify a data interface for severalreasons. For example, the data interfaces within a multi-homing devicemay be assigned duplicate private addresses. Also, multiple applicationswithin the multi-homing device may try to access the same service usingdifferent network data interfaces. In such scenarios, the applicationsmay bind to the same service access point (SAP), e.g., the same portnumber in case of UDP or TCP. As such, it may not be possible tocorrectly route a packet to the appropriate destination application.

A multi-homing device may also be vulnerable to spurious attacks via thedifferent data interfaces available at the multi-homing device. Forexample, in a typical multi-homing device, an application installedtherein can receive data from any network data interface as long as thedata interface is open for data transfer and the data protocoladdresses, e.g., IP address, port number, etc., match with that of theapplication.

Apart from security considerations, data network providers are alsoconcerned about the billing and usage of various services andtechnologies available to the mobile telephones on the data networks.For example, there is a certain cost associated with each new serviceand technology that a data network provider provides and carriers aretypically interested in hassle free discrete billing of various servicesused by the mobile phone user. If an application within a mobiletelephone is restricted to use certain data interfaces available at themobile telephone for data transfers, it can be easier for the carriernetwork to track the billing and cost associated with the usage of thedifferent technologies and services distinctly, based on per-datainterface usage.

Additionally, in a multi-homing networking device the port space fornetworking applications is usually shared between all of the datainterfaces available to the device. If an application is using aparticular port number for data transfer on a particular data interface,no other application can use the same port number—even if the otherapplication is using a completely different data interface. This can bean unnecessary restriction for a device that may need to run differentservices on different data interfaces but with the same port number. Forexample, the network device can include two different web servers thatuse the same port number, e.g., port eighty (80), but on different datainterfaces. Most network devices do not allow this flexibility. Someimplementations allow binding to a port for all of the data interfacesor for a specific data interface, i.e., one interface or all interfaces.

SUMMARY

A method of transmitting data from a multi-homing network device to adata network is disclosed and includes defining a network policy andtransmitting the network policy to a routing module. Further, the methodincludes receiving a route scope from the routing module. The routescope identifies a subset of data interfaces to the data network thatsatisfy the network policy wherein the subset of data interfaces areselected from a set of available data interfaces and wherein the subsetof data interfaces includes at least one data interfaces.

In a particular embodiment, the network policy identifies one or morecriteria for selecting the subset of data interfaces from the set ofavailable data interfaces. Further, the network policy defines two ormore data interfaces to be used for data transfer to and from anapplication. In another particular embodiment, the network policy isdefined by an application.

In yet another particular embodiment, the subset of data interfacesincludes a global system for mobile communications (GSM) data interface,a general packet radio service (GPRS) data interface, a universal mobiletelecommunications system (UMTS) data interface, a code divisionmultiple access (CDMA) data interface, a CDMA 2000 data interface, aCDMA evolution data optimized (EVDO) interface, a Bluetooth (BT) datainterface, an 802.11a data interface, an 802.11b data interface, an802.11g data interface, an 802.11i data interface, an 802.15 datainterface, an 802.16 data interface, a wideband CDMA (WCDMA) datainterface, an orthogonal frequency code division multiplexing (OFCDM)data interface, a global positioning system (GPS) data interface, or acombination thereof. In a particular embodiment, each of the interfacescan be an Internet protocol version 4 (IPv4) data interface, an IPversion 6 (IPv6) data interface, or another network protocol datainterface.

In still another particular embodiment, an application associated withthe network policy is bound to the subset of data interfaces identifiedby the route scope. In another embodiment, the method includesdetermining whether a preferred data interface within the subset of datainterfaces is available, opening a connection via the preferred datainterface when the preferred data interface is available, andtransmitting data via the preferred data interface. Further, the methodincludes determining whether a next preferred data interface within thesubset of data interfaces is available when the preferred data interfaceis unavailable, opening a connection via the next preferred datainterface, and transmitting data via the next preferred data interface.In still another embodiment, the method includes determining whether theconnection is interrupted, determining whether a next preferred datainterface is available when the connection is interrupted, opening aconnection via the next preferred data interface, and transmitting datavia the next preferred data interface.

In another embodiment, a multi-homing network device is disclosed andincludes a processor and a memory that is accessible to the processor.Further, at least one application is stored within the memory and atleast one network policy is stored within the memory. In thisembodiment, the at least one network policy defines at least one datainterface to be used by the application to transmit and receive data.

In yet another embodiment, a computer readable medium that is accessibleto a processor is disclosed and includes at least one application and atleast one network policy that is associated with the at least oneapplication. In this embodiment, the network policy identifies two ormore data interfaces of a multi-homing network device that can be usedto communicate data with respect to the application.

In still another embodiment, a method of binding data interfaces to anapplication is disclosed and includes receiving a network policy fromthe application and binding the application to a subset of datainterfaces but not all data interfaces within a set of available datainterfaces at a multi-homing network device. In this embodiment, thesubset of data interfaces includes at least one data interface.

In yet still another embodiment, a method of receiving data is disclosedand includes receiving a data packet from a data interface, comparing anInternet protocol (IP) address of the data interface to a destination IPaddress associated with the packet, and dropping the data packet whenthe IP address of the data interface does not match the destination IPaddress.

In another embodiment, a multi-homing network device is disclosed andincludes a processor, a memory that is accessible to the processor, anda routing module that is stored within the memory. In this embodiment,the routing module is configured to receive a network policy from anapplication and bind the application to a subset of data interfaceswithin a set of available data interfaces.

In still another embodiment, a computer readable medium that isaccessible to a processor is disclosed and includes a route scope. Inthis embodiment, the route scope indicates a subset of data interfaceswithin a set of available data interfaces at a multi-homing device andan application within the multi-homing device is bound to the subset ofdata interfaces for transmitting and receiving data.

In yet another embodiment, a method of binding an application to atleast one port within a network device is disclosed and includesreceiving a request to bind a port to a requesting application,determining whether an open application is bound to the port, andbinding the requesting application to the port when the open applicationis not bound to the port.

In still another embodiment, a user interface is disclosed and includesan application menu. In this embodiment, the application menu includes alist of applications that are installed at a multi-home network deviceand a user can select an application from the application menu in orderto edit at least one network setting associated with a selectedapplication.

In still yet another embodiment, a multi-homing network device isdisclosed and includes means for transmitting a network policy to arouting module and means for storing a route scope from the routingmodule in a socket. In this embodiment, the route scope identifies asubset of data interfaces to a data network that satisfy the networkpolicy and the subset of data interfaces are selected from a set ofavailable data interfaces. Further, the subset of data interfacesincludes at least one data interface.

In another embodiment, a multi-homing network device is disclosed andincludes means for receiving a network policy from an application andmeans for binding the application to a subset of data interfaces but notall data interfaces within a set of available data interfaces at themulti-homing network device. In this embodiment, the subset of datainterfaces includes at least one data interface.

In still another embodiment, a multi-homing network device is disclosedand includes means for receiving a data packet from a data interface,means for comparing an Internet protocol (IP) address of the datainterface to a destination IP address associated with the packet, andmeans for dropping the data packet when the IP address of the datainterface does not match the destination IP address.

In another embodiment, a multi-homing network device is disclosed andincludes means for receiving a request to bind a port to a requestingapplication, means for determining whether an open application is boundto the port, and means for binding the requesting application to theport when the open application is not bound to the port.

An advantage of one or more embodiments disclosed herein can includebinding an application to a subset of available network data interfaces.

Another advantage can include dropping incoming data packets that do notarrive on data interfaces approved by an application.

Yet another advantage can include transmitting data packets based on ahierarchy of available data interfaces for an application.

Other aspects, advantages, and features of the present disclosure willbecome apparent after review of the entire application, including thefollowing sections: Brief Description of the Drawings, DetailedDescription, and the Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The aspects and the attendant advantages of the embodiments describedherein will become more readily apparent by reference to the followingdetailed description when taken in conjunction with the accompanyingdrawings wherein:

FIG. 1 is a general diagram that illustrates a particular embodiment ofa communication system;

FIG. 2 is a general diagram that illustrates a data networking stack;

FIG. 3 is a flow chart illustrating a method of transmitting data;

FIG. 4 is a flow chart illustrating a method of binding an applicationto a subset of available data interfaces;

FIG. 5 is a flow chart illustrating a method of receiving data;

FIG. 6 is a flow chart illustrating a method of determining whether atemporary route scope conforms to a route scope of an application;

FIG. 7 is a general diagram illustrating a first example of processingan incoming data packet;

FIG. 8 is a general diagram illustrating a second example of processingan incoming data packet;

FIG. 9 is a general diagram illustrating a third example of processingan incoming data packet;

FIG. 10 is a general diagram illustrating a fourth example of processingan incoming data packet;

FIG. 11 is a flow chart illustrating a method of binding an applicationto one or more interfaces at a wireless device;

FIG. 12 is a diagram of a wireless device having a first graphical userdata interface;

FIG. 13 is a diagram of a wireless device having a second graphical userdata interface;

FIG. 14 is a diagram of a wireless device having a third graphical userdata interface; and

FIG. 15 is a diagram of a wireless device having a fourth graphical userdata interface.

DETAILED DESCRIPTION

Referring to FIG. 1, an exemplary, non-limiting communication system isshown and is generally designated 100. As shown, the system includes afirst network device 102 and a second network device 104. In aparticular embodiment, the first network device 102 and the secondnetwork device 104 can communicate via one or more of a first datanetwork 106, a second data network 108, a third data network 110, and anNth data network. In a particular embodiment, the data networks 106,108, 110, 112 can be a global system for mobile communications (GSM)network, a general packet radio service (GPRS) network, a universalmobile telecommunications system (UMTS) network, a code divisionmultiple access (CDMA) network, a CDMA 2000 network, a CDMA evolutiondata optimized (EVDO) network, a Bluetooth BT network, an 802.11anetwork, an 802.11b network, an 802.11g network, an 802.11 i network, an802.15 network, an 802.16 network, a wideband CDMA (WCDMA) network, anorthogonal frequency code division multiplexing (OFCDM) network, aglobal positioning system (GPS) network, or a combination thereof.

As shown in FIG. 1, the first network device 102 can include a processor114 and a memory 116 that is accessible to the processor 114. As shown,an application 118, a socket layer 119, and a routing module 120 can beembedded, or stored, within the memory 116 and can be executable by theprocessor 114. In a particular embodiment, the socket layer 119 includesone or more sockets that can be used by an application to send andreceive data. During operation, the application 118 transmits a networkpolicy 122 to the routing module 120 via the socket layer 119. In aparticular embodiment, the network policy 122 can identify a set of datainterfaces that can be used by an application to communicate with one ormore of the networks 106, 108, 110, 112. In response to the networkpolicy 122, the routing module 120 returns a route scope 124 to thesocket layer 119 and the route scope can be stored within the socketlayer 119 for a socket associated with the application 118. In aparticular embodiment, the route scope 124 includes a subset of datainterfaces that satisfy the network policy. The subset of datainterfaces are selected from the available data interfaces 132, 134, 136at the first network device 102.

FIG. 1 indicates that the first network device 102 can include a firsthardware port 126, a second hardware port 128, and an Nth hardware port130. Also, the network device 102 can include a first data interface132, a second data interface 134, and an Nth data interface 136.

In a particular embodiment, each of the data interfaces 132, 134, 136can be a global system for mobile communications (GSM) data interface, ageneral packet radio service (GPRS) data interface, a universal mobiletelecommunications system (UMTS) data interface, a code divisionmultiple access (CDMA) data interface, a CDMA 2000 data interface, aCDMA evolution data optimized (EVDO) interface, a Bluetooth BT datainterface, an 802.11a data interface, an 802.11b data interface, an802.11g data interface, an 802.11i data interface, an 802.15 datainterface, an 802.16 data interface, a wideband CDMA (WCDMA) datainterface, an orthogonal frequency code division multiplexing (OFCDM)data interface, a global positioning system (GPS) data interface, or acombination thereof. In a particular embodiment each of the interfacescan be an Internet protocol version 4 (IPv4) data interface, an IPversion 6 (IPv6) data interface, or another network protocol datainterface.

As illustrated in FIG. 1, the first network device 102 also includes atransceiver 138 that is coupled to the processor 114 and an antenna 140.In a particular embodiment, the transceiver 138 transmits and receivesdata packets and facilitates communication with one or more of thenetworks 106, 108, 110, 112. In a particular embodiment, the secondnetwork device 104 can include one or more of the element described inconjunction with the first network device 102.

In a particular embodiment, the first network device 102, or the secondnetwork device 104, is a multi-homing networking asset. Further, inorder to support the vast diversity of the data services, the firstnetwork device 102 includes multiple network data interfaces 132, 134,136. Each of the data interfaces 132, 134, 136 are capable of datatransfer once each data interface is configured to connect to anassociated network 106, 108, 110, 112. In a particular embodiment, withmulti-homing, one or more of the data interfaces 132, 134, 136 may beactive simultaneously and each active data interface 132, 134, 136 canprovide access to a different physical or logical network 106, 108, 110,112.

Moreover, in a particular embodiment, each active data interface 132,134, 136 includes a separate network address, e.g., IP address for IPnetworks, assigned thereto. Each of the network addresses can beglobally unique or one or more of the network addresses may beduplicated if assigned from a private space.

In a particular embodiment, multi-homing can allow the first networkdevice 102 to access different networks having different datatechnologies, e.g., CDMA, UMTS, GSM, etc. Further, multi-homing canallow the first network device 102 to access the available networks 106,108, 110, 112 based on the varying costs associated with the availablenetworks 106, 108, 110, 112. As such, the user, or applications withinthe first network device 102, is given more flexibility on the qualityand cost effectiveness desired. Multi-homing can also allow the firstnetwork device to access the available networks 106, 108, 110, 112 basedon the quality of services that the networks provide. A user may desirethat a particular application use a high quality network—regardless ofthe cost associated with using the network. On the other hand, the usermay instruct an application to not exceed a particular cost and only usenetworks below the cost—regardless of the quality of the networkconnection.

In a particular embodiment, multi-homing can allow the first networkdevice 102 to access different network types, e.g., IPv4, IPv6, IPX,etc. Also, multi-homing can allow applications within the first networkdevice 102 to access various services provided bydifferent-physical/logical networks. For example, a particular carriermay deploy different networks to provide different type of IP services,e.g., Internet, email, SMS, MMS, WAP, etc.

FIG. 2 illustrates an exemplary, non-limiting embodiment of a TCP/IPnetworking stack, generally designated 200. As shown, the networkingstack 200 includes a physical layer 202. A data interface layer 204 islocated over the physical layer 202. In a particular embodiment, thedata interface layer 204 includes a first data interface 206, a seconddata interface 208, a third data interface 210, and an Nth datainterface 212.

As depicted in FIG. 2, an Internet protocol (IP) layer 214 is locatedover the data interface layer 204. In an illustrative embodiment, the IPlayer 214 includes one or more IPs, e.g., IP version 4 (IPv4) 216 and IPversion 6 (IPv6) 218. FIG. 2 further shows a transport layer 220 overthe IP layer 214. The transport layer 220 can include one or morecommunication protocols, e.g., transmission control protocol (TCP) 222or user datagram protocol (UDP) 224. Further, a socket layer 226 can belocated over the transport layer 220. Also, one or more applications canbe located over the socket layer 226.

Referring to FIG. 3, a method of transmitting data from a network deviceto a data network is shown and commences at block 300. At block 300, anapplication within the network device transmits a network policy to arouting module within the network device. In a particular embodiment,the application and the routing module are concurrently executable by asingle processor. Alternatively, the application and routing module canbe executed by different processors.

In a particular embodiment, the network policy can identify a set ofdata interfaces that satisfy one or more criteria specified in thenetwork policy. For example, a network policy can specify the criteriaas all UMTS data interfaces, or all IPv4 data interfaces. Further, thenetwork policy can specify a quality of service criteria, e.g., amaximum delay value, a maximum jitter value, a bandwidth value, or acombination thereof. Also, the network policy can specify a maximumcost, communication technology type, one or more carriers, or acombination thereof. Before data transfer can be initiated by anapplication, the application can bring up a particular data interfaceamong a set of data interfaces that satisfy the network policy.

In another particular embodiment, the decision of which data interfaceto bring up, can be performed by the network management software of thedata stack. Further, the decision can be performed on the basis of amost favored route, e.g., based on the specified network policy. In aparticular embodiment, each data interface can include its own accesscontrol list (ACL), which is essentially a list of rules. Moreover, eachdata interface can evaluate access to thereto based on a network policyassociated with an application. As part of the evaluation, an ACL caneither restrict the access to a data interface or return a non-zeropriority number, e.g., 1-5, for that data interface. A non-zero prioritynumber signifies that the data interface is usable with the given policyand the priority number identifies the level of preference.

In an illustrative embodiment, a routing module can evaluate a networkpolicy associated with an application and an ACL associated with each ofthe available data interfaces and select the data interface with thehighest priority. As such, the routing module can bind the applicationto the data interface with the highest priority in order to send thedata out. In a particular embodiment, at any give time, many datainterfaces may be open for data transfer and each data interface can bebound to separate applications in order to allow transmit sidemulti-homing on the wireless device. If a particular data interface isnot open, it can be brought up to make it open for data communication.

Moving to block 302, a route scope is received from the routing module.Further, at block 303, the route scope can be stored within a socketlayer for a socket associated with the application. In a particularembodiment, the route scope indicates a subset of data interfaces thatsatisfy the network policy. Each data interface in the subset caninclude a priority number. As such, the subset of data interfaces can bearranged in a hierarchy from a preferred data interface to a leastpreferred data interface. In an illustrative embodiment, the subset ofdata interfaces is selected from a set of available data interfaces atthe network device.

At decision step 304, the network device determines whether theapplication is attempting to transmit data to a data network. If not,the method ends at state 306. If so, the method proceeds to decisionstep 308 and the network device determines whether the preferred datainterface within the route scope, i.e., within the subset of datainterfaces bound to the application, is available. If the preferred datainterface is available, the method moves to block 310 and the networkdevice opens a channel via the preferred data interface. Conversely, ifthe preferred data interface is not available, the method proceeds todecision step 312 and the network device determines whether a nextpreferred data interface within the route scope is available.

If a next preferred data interface is not available, the method moves toblock 314 and an error message is displayed to the user of the networkdevice, e.g., via a display at the network device. Otherwise, if a nextpreferred data interface is available, the method proceeds to block 310and the network device opens a channel via the data interface. In aparticular embodiment, there may be multiple iterations before the errormessage is displayed. In other words, there may be multiple nextpreferred data interfaces in the hierarchy of data interfaces. Forexample, the hierarchy of data interfaces can include a preferred datainterface, a first next preferred data interface, a second nextpreferred data interface, a third next preferred data interface, etc. Ina particular embodiment, the network device can keep checking for a nextavailable interface until all interfaces within the route scope areexhausted.

Proceeding to block 316, the application transmits data via theavailable data interface. At decision step 318, the network devicedetermines whether the connection is interrupted. If not, the methodmoves to decision step 320 and the network device determines whether thetransmission of data is complete. If so, the method ends at state 306.If the transmission of data is not complete, the method returns to block316 and continues as described.

Returning to decision step 318, if the connection is interrupted, themethod moves to decision step 322 and the network device determineswhether the next preferred data interface within the route scope isavailable. If not, the method ends at state 306. On the other hand, ifthe next preferred data interface is available, the method continues todecision step 324 and the network device determines whether the protocolfor the data transfer is connection oriented. If the protocol is notconnection oriented, e.g., the protocol is connectionless user datagramprotocol (UDP), the method moves to block 326 and the applicationseamlessly jumps to the next available data interface withoutinterrupting the connectivity. Conversely, if the protocol is connectionoriented, e.g., the protocol is transmission control protocol (TCP), themethod proceeds to block 328 and the application reconnects to the nextavailable data interface. If the protocol is TCP the connectivity willbe interrupted while the application reconnects via the new datainterface. From block 326 or block 328, the method proceeds to decisionstep 320 and continues as described.

In a particular embodiment, using the above described method, anapplication can specify a network policy for data transfer associatedwith the application. The network policy can restrict the datainterfaces on which the application sends and receives data. On thetransmit path, one data interface is chosen for the application fromsubset of approved data interfaces. In a particular embodiment, the datainterface that is chosen can be the most favorable, i.e., highestpriority, based on the network policy criteria, thereby optimizing thetransmit path. Further, in a particular embodiment, the application usesthe selected transmit data interface until the data transfer iscompleted or the data interface is lost. If the data interface is lost,a new data interface is chosen from the subset of data interfaces, ifavailable, based on priority. This allows the data transmission toconform to the network policy even if the highest priority datainterface is lost.

FIG. 4 depicts a method of binding an application to a subset of datainterfaces within a group of available data interfaces. Beginning atblock 400, a routing module receives a network policy from anapplication. At block 402, the routing module creates a route scopeaccording to network policy and available data interfaces. In aparticular embodiment, the route scope includes, or points to, a subsetof available data interfaces that satisfy the network policy of theapplication. Moving to block 404, the routing module binds theapplication to the available data interfaces within the route scope. Atblock 406, the routing module, returns the route scope to the socketlayer to be stored for the socket associated with the application. Themethod then ends at state 408.

Referring to FIG. 5, a method of receiving data at a network device froma data network is shown and commences at block 500. At block 500, thenetwork device receives a data packet at the IP layer of the data stackfrom a data interface. Moving to decision step 502, the network devicedetermines whether the destination IP address of the data packet is thesame as the IP address of data interface assigned to the application. Ifnot, the method proceeds to block 504 and the data packet is dropped.The method then ends at state 506.

If the destination IP address of the data packet is the same as the IPaddress of the data interface, the method moves to block 508 and thenetwork device searches for a socket associated with the data packet. Atdecision step 510, the network device determines whether the socket isfound. If not, the method moves to block 504 and the data packet isdropped. The method then ends at state 506.

At decision step 510, if the socket is found, the method proceeds toblock 512 and a route scope associated with the application isretrieved. At block 514, a temporary route scope for the data interfaceis created. In a particular embodiment, the temporary route scope iscreated by determining the index of the input data interface and turningthe corresponding bit to 1 and keeping every other bit in the temporaryroute scope as 0.

Moving to decision step, it is determined whether the temporary routescope conforms to the route scope associated with the application. FIG.6 illustrates a detailed embodiment of determining whether the temporaryroute scope conforms to the route scope associated with the application.If the temporary route scope conforms to the route scope of theapplication, the method moves to block 518 and the network devicecontinues the transport layer processing of the data packet. The methodthen ends at state 506.

If the temporary route scope does not conform to the route scope of theapplication, the method moves to block 520 and the network device dropsthe data packet. Proceeding to decision step 522, the network devicedetermines whether the current communication protocol is TCP or UDP. Ifthe current communication protocol is TCP, the method moves to block 524and the network device sends a reset (RST) message to the peer devicethat transmitted the data packet that is dropped. The method ends atstate 506. If the current communication protocol is UDP, the networkdevice sends an Internet control message protocol (ICMP) destinationunreachable port unreachable to the peer device that transmitted thedata packet that is dropped at the network device. The method then endsat state 506.

In a particular embodiment, using the method described above, when apacket arrives via a data interface for some connection it can berestricted to the data interfaces allowed in the route scope in twostages. For example, the first stage is a simple sanity check. Thisstage involves the comparison of the IP address of the data interfacethe packet came on and the destination address of the packet. The onlyexception to this being that the destination address should not be amulticast or a broadcast address. When the input packet is handed overto the IP layer, the IP layer is notified of the data interface that thepacket came in. If the destination IP address of the packet does notmatch to that of the data interface it came on then packet is droppedsilently. This restricts the packets to particular data interfaces withspecific IP addresses and prevents any routing errors happening for theinput packet.

FIG. 6 illustrates a method of determining whether a temporary routescope conforms to a route scope of an application. Beginning at block600, a route scope for an application is received. At block 602, atemporary route scope is created. Thereafter, at block 604, a bitwiseAND operation is performed on the route scope and the temporary routescope. Moving to block 606, it is determined whether the result of theAND operation is zero. If the result is zero, the method moves to block608 and the packet is dropped. The method then ends at state 610. On theother hand, if the result is not zero, the method moves to block 612 andthe data packet is kept. Then, the method ends at state 610.

In a particular embodiment, the route scope contains information aboutwhich data interfaces are allowed to receive data on for a particularapplication. The route scope can be maintained as a bit mask of allavailable data interfaces. When a data interface satisfies the networkpolicy for a particular application, the data interface is added to theroute scope associated with the particular application. For example, ifa fifth data interface, having an index five (5), satisfies the networkpolicy for the application, a bit number five (5) in the route scope forthe application is set to one (1) in order to include the fifth datainterface in the route scope for the application.

In a particular embodiment, when limiting the data received, all thedata interfaces that have priority greater than zero are included in theroute scope for the application. The method reviews the ACL for eachdata interface and includes all the data interfaces in the route scopefor the application that satisfy the network policy for the application.In a particular embodiment, the route scope can include one or more bitsthat are set to one (1) indicating that the application associated withthe route scope is allowed to receive data via one or more of datainterfaces.

In a particular embodiment, if an application binds to a specific IPaddress, the route scope can be restricted to include the datainterfaces with the requested IP address and that also match the networkpolicy. In another particular embodiment, route scope is created when anapplication creates a socket with a specific network policy. However,the route scope may be periodically updated.

FIG. 7 through FIG. 10 illustrate examples that conform to the methodsoutlined in FIG. 5 and FIG. 6. FIG. 7 depicts an example in which aninput packet is received and includes a destination address (10.0.0.1)that is the same as the address of the data interface (10.0.0.1). Assuch, the input packet is accepted.

FIG. 8 illustrates an example in which an input packet is received andincludes a destination address (10.0.0.1) that is different from theaddress of the input data interface (10.0.0.2) at which the input packetis received. As such, the input packet is dropped.

FIG. 9 illustrates an example in which an input packet is received on adata interface that satisfies the network policy of an application andis accepted. As shown, the bitwise AND operation that is performed onthe route scope of the application and the temporary route scope isnon-zero. As such, the input packet satisfies the network policy of theapplication.

FIG. 10 illustrates an example in which an input packet is received on adata interface that does not satisfy the network policy of anapplication. As shown, the bitwise AND operation that is performed onthe route scope of the application and the temporary route scope iszero. As such, the input packet violates the network policy of theapplication and the input packet is dropped.

In a particular embodiment, the dynamic nature of the state of the datainterfaces, and wireless networking, may affect the route scope that isassociated with each application within a network device. For example,due to the mobility of the network device, the network device may moveacross the coverage areas of several networks causing correspondingnetwork data interfaces to come up or go down. Also due to mobility, thepriority of one network, and an associated network data interface, mayincrease or decrease depending upon a type of network access that isavailable or a type of carrier that is providing service at a particularlocation at a particular time.

Due to the dynamic nature of wireless communication, there can beseveral triggers that may cause the route scopes associated with theapplications within the network device to change. Further, the routescopes associated with the applications need to be managed and changedwith the changing states of the data interfaces.

In a particular embodiment, whenever a data interface goes up or down,it can affect the route scope of various applications because thenetwork policy associated with some applications and data interfaces aredynamically configured. For example, when a UMTS data interface isbrought up, the UMTS connects to a different access point name (APN)each time, and provides a different type of service. When such a datainterface is brought up and is tied to a specific APN, that datainterface may no longer match the network policy of one or moreapplications within the network device. As such, bringing up aparticular data interface may shrink down the route scope for one ormore applications.

Similarly, when a particular data interface is brought down, it couldexpand the route scope associated with one or more applications. In aparticular embodiment, if a data interface is down, it still can beincluded in a route scope for an application and the application maypotentially use that data interface after it is brought up. Further, ina particular embodiment, some data interfaces, but not all datainterfaces may be brought up automatically to save costs. The additionaldata interfaces may be brought up when required, e.g., by a user or anapplication.

In a particular embodiment, when a network node changes the networkcoverage area, the route scope of one or more applications may change.For example, losing the coverage area of one network can cause anassociated data interface to become disabled until the data interface isenabled when the network device re-enters a coverage area. In aparticular embodiment, a disabled data interface cannot be brought updue to lack of network connectivity while a down data interface canpotentially be brought up and used for communication when needed.

In another particular embodiment, certain applications may be tightlybound to a single network data interface and that data interface is usedfor transmitting and receiving data. For such applications, the routescope has only one bit set and that bit can be set when the datainterface is brought up and reset to zero when the data interface isbrought down.

In a particular embodiment, the route scope can also change when thenetwork policy associated with the socket is changed. In such anembodiment, a new route scope can be calculated for that applicationaccording to the new network policy and the new route scope can bepropagated to the socket associated with the application. In anotherembodiment, if an application binds to a specific IP address, e.g.,using a bind( ) API call, the route scope can be restricted to datainterfaces which have the particular address to which the socket isbound. Due to mobility and network handoff, the data interface IPaddress can change and the route scope for the application may need tobe updated to exclude the previous data interface from the associatedroute scope.

Further, in a particular embodiment, if a single network data interfaceis capable of servicing various technological areas, e.g., CDMA, UMTS,etc., or network types, e.g., IPv4, IPv6 etc., and if such a datainterface hands off to a different technological area or network type,the route scopes which include this data interface need to be updatedand re-evaluated in order to determine whether the data interfacecontinues to satisfy the network policy of the application. In yetanother particular embodiment, for connected sockets, e.g., TCP sockets,once a connection has been established, e.g., using a connect( ) APIcall, the route scope can be restricted to only one interface that canconnect to the specified destination address.

In another particular embodiment, a network policy specified by theapplication may or may not include a loopback data interface. However,every socket may be allowed to send and receive packets on a loopbackdata interface. As such, a loopback data interface can be considered aspecial case of the data interfaces restricted through one or morenetwork policies. A loopback data interface can include a restrictionthat packets received with a loopback destination IP address should bereceived on the loopback data interface. This check can be performed atthe IP layer as first stage of data interface restriction for inputpackets, e.g., during an address comparison. For the transport layerrestriction, either the bit corresponding to the loopback data interfacemay be turned on for the route scope associated with each application ora special check can be performed at the transport layer for processingfor route scope.

Referring to FIG. 11, a method of binding an application to a port isshown and commences at block 1100. At block 1100, a routing modulewithin a network device receives request to bind a port to anapplication. At block 1102, the routing module reviews all open, oractive, applications. Moving to decision step 1104, the routing moduledetermines whether any open, or active, application is bound to the sameport to which the requesting application is attempting to bind. If not,the method proceeds to block 1106 and the routing module binds therequesting application to the port. The method then ends at state 1108.

On the other hand, at decision step 1104, if any open, or active,applications are bound to the same port to which the requestingapplication is attempting to bind, the method proceeds to block 1110 andthe routing module performs a bitwise AND operation on the route scopeof each open/active application and the route scope of the requestingapplication. Proceeding to decision step 1112, the routing moduledetermines whether the result of any bitwise AND operation is zero. Ifso, the method moves to block 1106 and the routing module binds therequesting application to the port setting the port in the socketassociated with the requesting application. The method ends at state1108.

Returning to decision step 1112, if the result of any bitwise ANDoperation is not zero, the method moves to block 1114 and the routingmodule does not bind the requesting application to the port. The methodthen ends at state 1108.

In a particular embodiment, when the route scope of a socket changes dueto one or more of the various reasons described above, the new routescope may have an effect on the port space separation. For example,during the recalculation of a route scope for an application, if one ormore data interfaces get removed from the route scope, a problem doesnot arise since the port space remains separate and since no newintersection between the route scopes of the sockets is created.However, if one or more data interfaces are added to the route scope,the addition of a data interface may create a conflict with the routescopes associated with other application. If the port numbers that areused by the applications with intersecting route scopes are same, thenetworking stack will be unable to decide which application to direct anincoming data packet that arrives on one of the intersecting datainterfaces.

In a particular embodiment, this potential conflict can resolved basedon the following approach: If the conflicting application is alreadyactively transferring data over the conflicting <port number, datainterface> pair, that application is left alone and the otherapplication is prevented from using that <port number, data interface>pair. If the conflicting application is not actively using the <portnumber, data interface> pair for data transfer, the <port number, datainterface> pair is disallowed for the conflicting applications based ona configurable policy.

In a particular embodiment, disallowing an application essentially meansthat the route scope of the disallowed application temporarily shrinksto exclude the conflicting data interface for the port number inquestion. This can be handled by defining a set of blocked <port number,data interface> pairs for each application, i.e., a blocked route scope.In a particular embodiment, a blocked route scope is the one that istemporarily blocked due to a conflict with another application but notdue to network policy mismatch.

In a non-limiting, exemplary embodiment, an entry in a blocked routescope can be removed: (1) when the competing application closes, (2)when the competing application rebinds to another port space, (3) whenthe disallowed application rebinds to a different port space, (4) whenthe network policy of the disallowed application changes, (5) when thenetwork policy of the competing application changes, or (6) when theroute scope of the one or more applications changes due to theconditions defined above.

In a particular embodiment, conditions (2) and (5) above can cause theroute scopes for other applications within the network device to beblocked. Further, in a particular embodiment, the conditions (3) and (4)may cause some entries to be removed from a blocked route scope whileother entries may be added due to new conflicts.

In a particular embodiment, the steps described above in conjunctionwith FIG. 3, FIG. 4, FIG. 5, FIG. 6, and FIG. 11 can be embodied assoftware that is stored within a memory, e.g., random access memory(RAM), a dynamic random access memory (DRAM), a static random accessmemory (SRAM), a read only memory (ROM), a masked ROM, a programmableread only memory (PROM), an erasable and programmable read only memory(EPROM), an electronically erasable and programmable read only memory(EEPROM), a non-volatile random access memory (NVRAM), a flash memory, ahard disk drive, or other storage means. Each of these method steps canbe stored individually or in combination with other method steps.

Further, in a particular embodiment, the method steps described above inconjunction with FIG. 3, FIG. 4, FIG. 5, FIG. 6, and FIG. 11 can beexecuted by a processor, a microprocessor, a controller, amicrocontroller, an application specific integrated circuit (ASIC), adigital signal processor (DSP, or other processing means. Each of thesemethod steps can be executed individually or in combination with othermethod steps.

FIG. 12 illustrates a wireless device that is generally designated 1200.As shown, the wireless device 1200 includes a display 1202 and a keypad1204. Further, the wireless device 1200 can include a microphone 1206and a speaker 1208. A user can speak into the microphone 1206 and listento incoming audio via the speaker 1208. As indicated in FIG. 12, asignal strength indicator 1210, a voicemail indicator 1212, and abattery level indicator 1214 can be displayed by the display 1202.

As depicted in FIG. 12, in an exemplary, non-limiting embodiment, thekeypad 1204 can include a directional button 1216 that a user can use tomove a cursor or selector bar around at the display 1202. Specifically,the user can use to the directional button 1216 to move a cursor orselector bar in any direction, e.g., up, down, left right, or anydiagonal direction. Further, in a particular embodiment, the keypad 1204can include an okay button 1218, a clear button 1220, and an end button1222. A user can use the okay button 1218, the clear button 1220, andthe end button 1222 to input answers in response to prompts presented atthe display 1202.

FIG. 12 further illustrates a first exemplary graphical user datainterface (GUI) 1250 that can be presented to a user via the display1202 of the wireless device 1200. As shown, the first GUI 1210 can ainclude header 1252 that indicates the purpose of the first GUI 1250. Asshown, in an illustrative embodiment, the header 1252 is labeled “EditNetwork Settings.” As such, a user can surmise that the first GUI 1250can be used to edit network settings.

FIG. 12 also indicates that the first GUI 1250 can include anapplication menu 1254. In a particular embodiment, the application menu1254 includes a list of applications that are installed at the wirelessdevice 1200 that require network access. For example, the applicationmenu 1254 includes a first application, a second application, a thirdapplication, and an Nth application. As shown, the first GUI 1250 alsoincludes a selector bar 1256 that a user can move up and down within theapplication menu 1254 using the directional button 1216 at the keypad1204. A user can move the selector bar 1256 to an application, e.g., thethird application, and select the okay button 1218 at the keypad 1204 inorder to access a second GUI 1300 shown in FIG. 13.

FIG. 13 illustrates a second exemplary GUI, designated 1300, that can beused edit the settings for an application, e.g., the third applicationselected at using the first GUI 1250 (FIG. 12). As depicted in FIG. 13,the second GUI 1300 can a include header 1302 that indicates the purposeof the second GUI 1300. In an illustrative embodiment, the header 1302of the second GUI 1300 is labeled “App. 3—Edit Network Settings”. Assuch, a user can determine that the second GUI 1300 can be used to editnetwork settings for the third application.

In an alternative embodiment, if the user selects the first applicationat the first GUI 1250 (FIG. 12), the header 1302 of the second GUI 1300can be labeled “App. 1—Edit Network Settings”.

As shown in FIG. 13, the second GUI 1300 can include a network menu 1304that includes a list of networks, or network data interfaces, that areavailable at the wireless device 1200. For example, the network menu1304 includes a first network, a second network, a third network, and anNth network. The second GUI 1300 also includes a selector bar 1306 thata user can move up and down within the network menu 1304 using thedirectional button 1216 at the keypad 1204. A user can move the selectorbar 1306 to a network, e.g., the second application, and select an addsoft button 1308 or a remove soft button 1310 in order to add or removea network to a list of approved networks for a particular applicationthat is installed at the wireless device 1200.

As shown, the second GUI 1300 also includes a set priority soft button1312 that is displayed at the display 1202. In a particular embodiment,a user can select the set priority soft button 1312 in order toestablish a hierarchy of networks approved for use by a particularapplication within the wireless device 1200. When the set priority softbutton 1312 is selected, a third GUI 1400 can be presented to the uservia the display 1202. Alternatively, predefined ACLs can be used todescribe network policy and assign priority to the data networks.

Referring to FIG. 14, the third GUI 1400 is shown. As depicted in FIG.14, the third GUI 1400 can a include header 1402 that indicates thepurpose of the third GUI 1400. For example, the header 1402 of the thirdGUI 1400 is labeled “Network Priority—App. 3”. As such, a user candetermine that the third GUI 1400 can be used to edit the networkpriority for the networks approved for use by the third application.

In an alternative embodiment, if the user selects the first applicationat the first GUI 1250 (FIG. 12) and the user selects the set prioritysoft button 1312 at the second GUI 1300 (FIG. 13), the header 1402 ofthe third GUI 1400 may be labeled “Network Priority—App. 1”.

As shown in FIG. 14, the third GUI 1400 can include a network prioritymenu 1404 that includes a list of networks, or network data interfaces,that are approved for use by the third application. Also, the networkpriority menu 1404 indicates the priority of each approved network, ornetwork data interface. For example, the network priority menu 1404includes a third network with a first priority, a first network with asecond priority, a fifth network with a third priority, and an fourthnetwork with a fourth priority.

The third GUI 1400 also includes a selector bar 1406 that a user canmove up and down within the network priority menu 1404 using thedirectional button 1216 at the keypad 1204. A user can move the selectorbar 1406 to a network, e.g., the first application, and select an upsoft button 1408 or a down soft button 1410 in order to move the firstnetwork up or down within the network priority menu 1404. As such, auser can define the priority of networks that an application can utilizeduring data transfer.

FIG. 15 illustrates a fourth GUI 1500 that can be presented to a userwhen an attempt to send a data packet to an application is prevented. Asdepicted in FIG. 15, the fourth GUI 1500 can a include header 1502 thatindicates the purpose of the fourth GUI 1500. For example, the header1502 of the fourth GUI 1500 is labeled “Error Message”. As such, a usercan surmise that the wireless device has encountered an error. FIG. 15further indicates that the fourth GUI 1500 can include an error message1504 that can be presented to the user via the display 1202. In anexemplary, non-limiting embodiment, the error message indicates“Incoming data packet dropped. Error logged.” As such, the user knowsthat an outside device attempted to transmit a data packet to thewireless device, e.g., an application within the wireless device, andthat the data packet was dropped for being suspicious. In a particularembodiment, errors can be logged at the wireless device. Alternatively,errors can be logged at a network device at the network from which thesuspicious packet is received.

In a particular embodiment, each GUI 1250, 1300, 1400, 1500 describedabove is a stand-alone GUI. Alternatively, the GUIs 1250, 1300, 1400,1500 described above are part if a single GUI having multiple pages.

With the configuration of structure described herein, the system andmethod to support data applications in a multi-homing, multi-modecommunication device provides a way for applications within a networkdevice to specify which data interface to use for data networking. Forexample, a particular network data interface within a network device mayprovide access to a general network, e.g., the Internet, while anothernetwork data interface may provide access to a private corporateIntranet. Also, the network device can include a first email clientapplication to access email from the private corporate network and asecond email client application to retrieve personal email over theInternet.

In a particular embodiment, the network device can include a “special”browser for access to a private Intranet and an “of the shelf” browserfor general Internet access. Also, the network device can includemultiple GPS engines and each GPS engine can access location informationfrom a particular network via a data interface specified by the GPSengine. Additionally, in a particular embodiment, a name resolver, e.g.,a domain name system (DNS), that communicates with the network devicecan resolve a name, or address, for a specific network since there couldbe duplicate names, or addresses, configured in two private networks.

Further, with the configuration of structure described herein, thesystem and method can restrict the number of data interfaces on which anapplication can receive the data. This provides a relatively a higherlevel of security to the protocol stack and the applications within thenetwork device. Also, the system and method provides a way to restrictincoming data so that the incoming data is communicated to a particularapplication based on the data interface, or data interfaces, on whichthe data is received. The system can utilize a network policy associatedwith each application in order to identify the data interfaces that areallowed for data transfer for each application.

Moreover, the system and method described herein can allow applicationsto bind to specific ports for one, more, or all data interfaces. Forother protocol stacks, e.g., non-TCP/UDP/IP, applications can be allowedto gain access to services over a set of data interfaces.

Those of skill would further appreciate that the various illustrativelogical blocks, configurations, modules, circuits, and algorithm stepsdescribed in connection with the embodiments disclosed herein may beimplemented as electronic hardware, computer software, or combinationsof both. To clearly illustrate this interchangeability of hardware andsoftware, various illustrative components, blocks, configurations,modules, circuits, and steps have been described above generally interms of their functionality. Whether such functionality is implementedas hardware or software depends upon the particular application anddesign constraints imposed on the overall system. Skilled artisans mayimplement the described functionality in varying ways for eachparticular application, but such implementation decisions should not beinterpreted as causing a departure from the scope of the presentdisclosure.

The steps of the methods, or algorithms, described in connection withthe embodiments disclosed herein may be embodied directly in hardware,in a software module executed by a processor, or in a combination of thetwo. A software module may reside in RAM memory, flash memory, ROMmemory, PROM memory, EPROM memory, EEPROM memory, registers, hard disk,a removable disk, a CD-ROM, or any other form of storage medium known inthe art. An exemplary storage medium is coupled to the processor suchthat the processor can read information from, and write information to,the storage medium. In the alternative, the storage medium may beintegral to the processor. The processor and the storage medium mayreside in an ASIC. The ASIC may reside in a computing device or a userterminal. In the alternative, the processor and the storage medium mayreside as discrete components in a computing device or user terminal.

The previous description of the disclosed embodiments is provided toenable any person skilled in the art to make or use the presentdisclosure. Various modifications to these embodiments will be readilyapparent to those skilled in the art, and the generic principles definedherein may be applied to other embodiments without departing from thespirit or scope of the disclosure. Thus, the present disclosure is notintended to be limited to the embodiments shown herein but is to beaccorded the widest scope consistent with the principles and novelfeatures as defined by the following claims.

1. A method of transmitting and receiving data to and from amulti-homing network device to a data network, the method comprising:defining a network policy; transmitting the network policy to a routingmodule; and receiving a route scope from the routing module, wherein theroute scope identifies a subset of data interfaces to the data networkthat satisfy the network policy wherein the subset of data interfacesare selected from a set of available data interfaces and wherein thesubset of data interfaces includes at least one data interface.
 2. Themethod of claim 1, wherein the network policy identifies one or morecriteria for selecting the subset of data interfaces from the set ofavailable data interfaces.
 3. The method of claim 2, wherein the networkpolicy defines two or more data interfaces to be used for data transferto and from an application.
 4. The method of claim 3, wherein thenetwork policy is defined by an application.
 5. The method of claim 1,wherein the subset of data interfaces includes a global system formobile communications (GSM) data interface, a general packet radioservice (GPRS) data interface, a universal mobile telecommunicationssystem (UMTS) data interface, a code division multiple access (CDMA)data interface, a CDMA 2000 data interface, a CDMA evolution dataoptimized (EVDO) interface, a Bluetooth (BT) data interface, an 802.11adata interface, an 802.11b data interface, an 802.11g data interface, an802.11i data interface, an 802.15 data interface, an 802.16 datainterface, a wideband CDMA (WCDMA) data interface, an orthogonalfrequency code division multiplexing (OFCDM) data interface, a globalpositioning system (GPS) data interface, or a combination thereof. 6.The method of claim 1, wherein an application associated with thenetwork policy is bound to the subset of data interfaces identified bythe route scope.
 7. The method of claim 6, further comprising:determining whether a preferred data interface within the subset of datainterfaces is available; opening a connection via the preferred datainterface when the preferred data interface is available; andtransmitting data via the preferred data interface.
 8. The method ofclaim 7, further comprising: determining whether a next preferred datainterface within the subset of data interfaces is available when thepreferred data interface is unavailable; opening a connection via thenext preferred data interface; and transmitting data via the nextpreferred data interface.
 9. The method of claim 7, further comprising:determining whether the connection is interrupted; determining whether anext preferred data interface is available, when the connection isinterrupted; opening a connection via the next preferred data interface;and transmitting data via the next preferred data interface.
 10. Amulti-homing network device, comprising: a processor; a memoryaccessible to the processor; at least one application stored within thememory; and at least one network policy stored within the memory,wherein the at least one network policy defines at least one datainterface to be used by the application to transmit and receive data.11. The multi-homing network device of claim 10, further comprising aroute scope stored within the memory, wherein the route scope isreceived from a routing module, wherein the route scope includes asubset of data interfaces that satisfy the network policy wherein thesubset of data interfaces are selected from a set of available datainterfaces.
 12. The multi-homing network device of claim 11, wherein thesubset of data interfaces includes a global system for mobilecommunications (GSM) data interface, a general packet radio service(GPRS) data interface, a universal mobile telecommunications system(UMTS) data interface, a code division multiple access (CDMA) datainterface, a CDMA 2000 data interface, a CDMA evolution data optimized(EVDO) interface, a Bluetooth (BT) data interface, an 802.11a datainterface, an 802.11b data interface, an 802.11g data interface, an802.11i data interface, an 802.15 data interface, an 802.16 datainterface, a wideband CDMA (WCDMA) data interface, an orthogonalfrequency code division multiplexing (OFCDM) data interface, a globalpositioning system (GPS) data interface, or a combination thereof. 13.The multi-homing network device of claim 11, wherein the route scope isgenerated by a routing module based on the network policy.
 14. Themulti-homing network device of claim 11, wherein the subset of datainterfaces are organized in a hierarchy and the multi-homing networkdevice attempts to establish communication via each of the subset ofdata interfaces one at a time based on a first available data interfacewithin the hierarchy.
 15. The multi-homing network device of claim 10,further comprising: a transceiver coupled to the processor; and anantenna coupled to the transceiver.
 16. The multi-homing network deviceof claim 10, further comprising a plurality of data interfaces, whereineach of the plurality of data interfaces provides access to a differentdata network.
 17. The multi-homing network device of claim 16, whereineach of the plurality of data interfaces includes an access control list(ACL), wherein the ACL restricts the access to a corresponding datainterface.
 18. The multi-homing network device of claim 17, wherein theACL returns a non-zero priority number, wherein the non-zero prioritynumber indicates that the corresponding data interface is usable with aparticular network policy.
 19. The multi-homing network device of claim18, wherein the non-zero priority number identifies a level ofpreference associated with the corresponding data interface.
 20. Themulti-homing network device of claim 10, wherein a first applicationwithin the multi-homing network device accesses a first network via afirst data interface and a second application within the multi-homingnetwork device accesses a second network via a second data interface.21. A computer readable medium accessible to a processor, the computerreadable medium comprising: at least one application; and at least onenetwork policy associated with the at least one application, wherein thenetwork policy identifies two or more data interfaces of a multi-homingnetwork device to communicate data with respect to the application. 22.The computer readable medium of claim 21, further comprising a routescope wherein the route scope complies with the network policy andincludes a subset of at least one data interface selected from a set ofavailable data interfaces at a device in which the computer readablemedium is installed.
 23. The computer readable medium of claim 22,wherein the route scope is generated by a routing module at leastpartially based on the network policy.
 24. A method of binding datainterfaces to an application, the method comprising: receiving a networkpolicy from the application; and binding the application to a subset ofdata interfaces but not all data interfaces within a set of availabledata interfaces at a multi-homing network device, wherein the subset ofdata interfaces includes at least one data interface.
 25. The method ofclaim 24, further comprising creating a route scope that points to thesubset of data interfaces to which the application is bound.
 26. Themethod of claim 25, further comprising storing the route scope in asocket associated with the application.
 27. The method of claim 26,wherein the network policy identifies two or more data interfaces to beused to transfer data to and from the application.
 28. The method ofclaim 25, wherein the route scope is a bit mask of the set of availabledata interfaces.
 29. A method of receiving data, comprising: receiving adata packet from a data interface; comparing an Internet protocol (IP)address of the data interface to a destination IP address associatedwith the packet; and dropping the data packet when the IP address of thedata interface does not match the destination IP address.
 30. The methodof claim 29, further comprising determining whether the data packetbelongs to a socket when the IP address of the data interface matchesthe destination IP address.
 31. The method of claim 30, furthercomprising dropping the data packet when the data packet does not belongto a socket associated with the application.
 32. The method of claim 30,further comprising retrieving a route scope for an applicationassociated with the data packet when the data packet includes thetransport control block.
 33. The method of claim 32, further comprisingcreating a temporary route scope for a data interface on which thepacket is received.
 34. The method of claim 33, further comprisingdetermining whether the temporary route scope conforms to the routescope.
 35. The method of claim 34, further comprising transferring thedata packet to the application when the temporary route scope conformsto the route scope.
 36. The method of claim 34, further comprisingdropping the packet when the temporary route scope does not conform tothe route scope.
 37. The method of claim 36, responding to a peer devicewith a message indicating the data packet is dropped.
 38. The method ofclaim 33, further comprising performing a bitwise AND operation on thetemporary route scope and the route scope to generate a result.
 39. Themethod of claim 38, further comprising dropping the data packet when theresult is zero.
 40. The method of claim 38, further comprising keepingthe data packet when the result is non-zero.
 41. A multi-homing networkdevice, comprising: a processor; a memory accessible to the processor; arouting module stored within the memory, wherein the routing module isconfigured to: receive a network policy from an application; and bindthe application to a subset of data interfaces within a set of availabledata interfaces.
 42. The multi-homing network device of claim 41,wherein the routing module is further configured to create a route scopeat least partially based on the network policy.
 43. The multi-homingnetwork device of claim 42, wherein the route scope includes anindication of the subset data interfaces to which the application isbound.
 44. The multi-homing network device of claim 10, furthercomprising: a transceiver coupled to the processor; and an antennacoupled to the transceiver.
 45. A computer readable medium accessible toa processor, the computer readable medium comprising: a route scope,wherein the route scope indicates a subset of data interfaces within aset of available data interfaces at a multi-homing device, wherein anapplication is bound to the subset of data interfaces for transmittingand receiving data.
 46. The computer readable medium of claim 45,wherein the route scope is generated at least partially based on anetwork policy received from the application.
 47. The computer readablemedium of claim 45, wherein the route scope is generated by a routingmodule executable by the processor.
 48. The computer readable medium ofclaim 45, wherein the route scope is a bit mask of the set of availabledata interfaces.
 49. A method of binding an application to at least oneport within a network device, the method comprising: receiving a requestto bind a port to a requesting application; determining whether an openapplication is bound to the port; and binding the requesting applicationto the port when the open application is not bound to the port.
 50. Themethod of claim 49, further comprising: performing a bitwise ANDoperation on a first route scope associated with the open applicationand a second route scope associated with the requesting application whenthe open application is bound to the port.
 51. The method of claim 50,further comprising binding the requesting application to the port when aresult of the bitwise AND operation is zero.
 52. The method of claim 51,further comprising: preventing the requesting application from bindingto the port when the result of the bitwise AND operation is not zero.53. A user interface, comprising: an application menu, wherein theapplication menu includes a list of applications that are installed at amulti-home network device and wherein a user can select an applicationfrom the application menu in order to edit at least one network settingassociated with a selected application.
 54. The user interface of claim53, further comprising a network menu that includes a list of networksthat are available at the multi-homing network device.
 55. The userinterface of claim 53, wherein a user can select a network from thenetwork menu and associate a selected network to the selectedapplication.
 56. The user interface of claim 55, further comprising anetwork priority menu that includes a list of networks approved for useby the selected application.
 57. The user interface of claim 56, whereinthe network priority menu indicates a priority associated with eachnetwork listed at the network priority menu and wherein the selectedapplication communicates with each network based on the priorityassigned thereto.
 58. The user interface of claim 57, wherein thepriority associated with each network is assigned by a user.
 59. Amulti-homing network device, comprising: means for transmitting anetwork policy to a routing module; and means for receiving a routescope from the routing module, wherein the route scope identifies asubset of data interfaces to a data network that satisfy the networkpolicy wherein the subset of data interfaces are selected from a set ofavailable data interfaces and wherein the subset of data interfacesincludes at least one data interfaces.
 60. A multi-homing networkdevice, comprising: means for binding an application to a subset of datainterfaces but not all data interfaces within a set of available datainterfaces at the multi-homing network device, wherein the subset ofdata interfaces includes at least one data interface.
 61. A multi-homingnetwork device, comprising: means for receiving a data packet from adata interface; means for comparing an Internet protocol (IP) address ofthe data interface to a destination IP address associated with thepacket; and means for dropping the data packet when the IP address ofthe data interface does not match the destination IP address.
 62. Amulti-homing network device, comprising: means for receiving a requestto bind a port to a requesting application; means for determiningwhether an open application is bound to the port; and means for bindingthe requesting application to the port when the open application is notbound to the port.